1. Technical Field
This invention relates generally to instruction processing devices and, more particularly, to an apparatus and method for executing program instructions to carry out routines with different timing resolutions.
2. Discussion
It is widely known that programmed functions or routines are generally carried out by sequentially executing programmed sets of instructions. The programmed instructions are commonly stored in memory from which the instructions are fetched, read and then executed. Instructions are generally processed as a function of time to carry out the programmed routines for a given application. Generally speaking, an amount of time is required in order to process a given set of instructions. This amount of time for handling programmed instructions for each routine is commonly referred to as total execution time. The effective or average time to execute each instruction is commonly referred to as instruction resolution or timing resolution.
Different functions often require different amounts of timing resolution. For example, a timing resolution of seven microseconds may be desired in order to carry out the instructions necessary to control fuel injection in an automotive vehicle application. Other automotive-related functions such as spark timing control may require a lower (i.e., coarser) resolution of fifteen microseconds, while still other signal processing functions such as automatic transmission control functions may require a higher (i.e., finer) resolution of one or two microseconds, for example.
To perform various functions related to a given application, such as those associated with an automotive vehicle application, different timing resolutions are often required for different functions. In the past, conventional automotive timing devices have been employed to process a single function or a plurality of functions which share a common timing resolution. In order to realize different timing resolutions, conventional approaches have often required separate timing devices. With such prior approaches, each device was generally designed to process programmed functions at a predetermined timing resolution.
The conventional approaches often generally require several timing devices in order to accommodate a variety of functions which require differing levels of timing resolution. Requiring multiple timing devices results in multiple pieces of like hardware and similar software which adds to the overall cost and size of the necessary processing hardware and software. In addition, the requirement of separate individual processing devices may result in only partial utilization of available processing capability in each of the devices that are employed.
It is therefore desirable to provide for a programmable apparatus which is capable of carrying out a plurality of programmed functions, each capable of having different timing resolutions.
More particularly, it is desirable to provide for a programmable timer apparatus that can perform multiple programmed functions with differing timing resolutions for use with automotive vehicle applications so as to optimize hardware and software resources.
It is further desirable to provide a method of executing programmed functions with a single programmable apparatus to achieve different timing resolutions for different functions.